AS & A Level Chemistry - 9701 Paper 1 2024 Spring Zone 2

Which species contains the same number of neutrons as $^{14}_{6}\text{C}$ and the same number of electrons as $^{23}_{11}\text{Na}^+$?

Which process has the largest enthalpy change per mole?

Which sodium compound contains 74.2% by mass of sodium?

What is the maximum volume of sulfur dioxide gas measured at room conditions produced from burning 100\,\text{dm}^3 of diesel fuel containing 0.834\,\text{g} of sulfur?

Which row shows the correct number of covalent bonds in a molecule of methylpropene?
[Table_1]

Aluminium chloride exists as $\text{Al}_2\text{Cl}_6$ molecules at room temperature. When heated to a high temperature, $\text{AlCl}_3$ molecules are formed.
What are the arrangements of the bonding pairs of electrons around the aluminium atom in the two forms of aluminium chloride?
[Table_1]

The table shows the physical properties of four substances. Which substance has a giant covalent structure?

At room temperature and pressure, $\text{H}_2\text{O}$ is a liquid and $\text{H}_2\text{S}$ is a gas.
What is the reason for this difference of state?

The enthalpy change for a reaction can be calculated from values of:
• enthalpies of formation, $\Delta H^{\circ}_f$
• enthalpies of combustion, $\Delta H^{\circ}_c$
• bond energies, $E$.

The enthalpy change of the reaction given = $\Delta H^{\circ}_r$.

$$2C_2H_6(g) + 3O_2(g) \rightarrow 2CH_4(g) + 2CO_2(g) + 2H_2O(l)$$
Which expression could be used to calculate $\Delta H^{\circ}_r$?

Which reaction has an enthalpy change equal to the standard enthalpy change of formation of propane?

One of the reactions in the rechargeable lead/acid battery is shown.
$\text{Pb(s) + PbO}_2\text{(s) + 4H}^+\text{(aq) + 2SO}_4^{2-}\text{(aq)} \rightarrow 2\text{PbSO}_4\text{(s) + 2H}_2\text{O(l)}$
Which statement about this reaction is correct?

KMnO₄ is an oxidising agent. Its reaction with Fe²⁺ is shown in the following ionic equation.
$$...X...MnO_4^- + ......Fe^{2+} + ......H^+ \rightarrow ......Mn^{2+} + ...Y...Fe^{3+} + ......H_2O$$
What are X and Y when the equation is balanced?

Nitrogen and hydrogen are mixed in a reaction vessel. The reaction reaches equilibrium giving a mixture of nitrogen, hydrogen and ammonia gases.

$N_2 + 3H_2 \rightleftharpoons 2NH_3$

The mixture of gases present at equilibrium at a total pressure of 300 atm is shown.

[Table_1]

What is the equilibrium constant, $K_p$, for the forward reaction?

A mixture of hydrogen gas and iodine gas is placed in a reaction vessel of volume $V$ at temperature $T$.
The reaction $\text{H}_2 + \text{I}_2 \rightleftharpoons 2\text{HI}$ is allowed to come to equilibrium.
All substances remain in the gaseous state.
Argon gas is then pumped into the reaction vessel. The temperature in the vessel is maintained at $T$.
How are the rate of the forward reaction and the partial pressure of HI at equilibrium affected?
[Table_1]

Two experiments are carried out to study the reaction between zinc and sulfuric acid.

experiment 1: Small lumps of zinc are added to excess dilute sulfuric acid.
experiment 2: The reaction is carried out at a lower temperature and with one other change.

Both experiments produce the same total volume of gas and are completed in the same time.

What is the second change made in experiment 2?

The relative magnitude of the property X of five elements is shown. P, Q, R, S and T are all in Period 3 and have consecutive atomic numbers. The letters are not the actual chemical symbols of the elements.
Which row is correct for property X and element R?

Element X is in Period 3. Element X reacts with oxygen to produce a solid, Y.
When solid Y is added to water, a solution with a pH of less than 7 is produced.
What is the identity of element X?

This question refers to isolated gaseous species.
The species $\text{F}^-$, Ne and $\text{Na}^+$ are isoelectronic. This means they have the same number of electrons.
In which order do their radii increase?
[Table below]

Separate samples of magnesium and calcium are added to an excess of dilute sulfuric acid. The observations are summarised in the table.

[Table_1]

Which statement explains the difference in these observations?

Dolomite is a double carbonate, $\text{CaMg(CO}_3)_2$, and can be used instead of calcium carbonate for treating acidic soils. The three statements all refer to the agricultural use of these carbonates.
1. Dolomite and calcium carbonate are both less soluble than $\text{Ca(OH)}_2$.
2. One mole of dolomite has the same neutralising effect as one mole of calcium carbonate.
3. Dolomite and calcium carbonate both increase the pH of acidic soils.
Which statements are correct?

This question is about two salts, NaI and NaCl.
The two solid salts are separately added to warm concentrated $H_2SO_4$ and the results noted.
Aqueous solutions of the two salts are separately added to $AgNO_3$(aq) and then concentrated $NH_3$(aq) is added and the results noted.
Which row is correct?

[Table_1]

The diagram shows the process of adding calcium nitrate and strontium nitrate to separate boiling tubes and heating them. Identical conditions are used.

As the reactions proceed, the water containing universal indicator changes colour.
Which row describes the colour change and identifies the nitrate that causes the quickest colour change?

The equations for three reactions involving chlorine or its compounds are listed.

1\) \[2KClO_3 \rightarrow 2KCl + 3O_2\]
2\) \[4KClO_3 \rightarrow 3KClO_4 + KCl\]
3\) \[6KOH + 3Cl_2 \rightarrow 3H_2O + 5KCl + KClO_3\]

Which statement about these equations is correct?

Nitrogen monoxide, NO, is a primary pollutant produced by petrol engines and is found in their exhaust gases.
Which reaction occurs in a catalytic converter and decreases the emission of nitrogen monoxide?

The diagram shows the structure of the naturally occurring molecule cholesterol. Student X stated that the 17 carbon atoms in the 4 rings all lie in the same plane. Student Y stated that this molecule displays cis/trans isomerism at the C=C double bond. Which students are correct?

The drug cortisone has the formula shown.
In addition to those chiral centres marked by an asterisk (*), how many other chiral centres are present in the cortisone molecule?

But-2-ene reacts with cold dilute acidified KMnO$_4$ to give product X.
But-2-ene reacts with hot concentrated acidified KMnO$_4$ to give product Y.
Which statement about product X and product Y is correct?

A sequence of reactions takes place. The major product is compound Z.

What is compound Z?

Which statement is correct?

In the hydrolysis of bromoethane by aqueous NaOH, what is the nature of the attacking group and of the leaving group?

[Table]

| attacking group | leaving group |
|----------------|---------------|
| A | electrophile | electrophile |
| B | electrophile | nucleophile |
| C | nucleophile | electrophile |
| D | nucleophile | nucleophile |

X is an organic compound containing the elements carbon, hydrogen and oxygen only.
The table shows the observations made from three chemical tests carried out on X.

[Table_1]

What is a possible structure of X?

How many moles of oxygen gas are needed for the complete combustion of 1 mol of $(CH_3)_3COH$?

In which pair will each compound give a different visible result with alkaline $I_2(aq)$?

Which reagent gives a positive result with propanone?

Esters can be hydrolysed with an aqueous alkali or an aqueous acid to form two products. The table compares the two methods. Which row is correct?
[Table_1]

Structural isomerism only should be considered when answering this question.
How many compounds with molecular formula $C_5H_{11}Br$ are primary halogenoalkanes?

Compound Z is formed by the reaction scheme shown.

What is the formula of compound Z?

Hydroxyethanal, HOCH$_2$CHO, is heated under reflux with an excess of acidified K$_2$Cr$_2$O$_7$ until no further oxidation takes place. What is the skeletal formula of the organic product?

The formula shows the repeat unit of an addition polymer.
$$-\text{CH(CH}_3\text{)CH(CH}_2\text{CH}_3\text{)-}$$
What is the correct name of the monomer from which this polymer is made?

The infrared spectrum of a compound is shown.


bond functional groups containing the bond characteristic infrared absorption range
(in wavenumbers)/cm^{-1}
C–O hydroxy, ester 1040–1300
C=C aromatic compound, alkene 1500–1680
C=O amide 1640–1690
carbonyl, carboxyl 1670–1740
ester 1710–1750
C≡N nitrile 2200–2250
C–H alkane 2850–2950
N–H amine, amide 3300–3500
O–H carboxyl 2500–3000
hydroxy 3200–3600
Which functional group could the compound contain?